Erythrocyte sedimentation rate II. Effects of tilt angle in saline solution

We have measured the sedimentation curves of swine erythrocytes in a physiological saline solution in inclined glass tubes. The curves are well fitted to the exponential type equation l = a[1 - exp(-bt)] for the tilt angle theta in the range of theta less than 80 degrees and hematocrits from 10 to 50%, where l and t are the medium length along the tube and the elapsed time from the sample injection, respectively. The coefficient a increases with theta and b is proportional to sin theta. The erythrocyte sedimentation rate ESR(theta) = (d l/dt)t----0 determined from the above empirical equation increases with the increase in sin theta roughly linearly. The experimental results are discussed with reference to the Ponder-Nakamura-Kuroda theory and some recent theories.     

Sister chromatid differential staining by direct staining in Na2HPO4-Giemsa solution and the mechanism involved

The direct staining of BrdU-substituted Chinese hamster chromosomes in a Na₂HPO₄-Giemsa solution without any pretreatments resulted in a B-dark type SCD in which bifilarly substituted (BB) chromatids stained dark and unifilarly substituted (TB) chromatids stained light. Detailed examinations of the staining process suggested that the Na₂HPO₄ solution acts to collapse chromosomes whereas the Giemsa dye works to reconstruct the collapsed chromosomes, and that during the reconstruction process preferential binding of the Giemsa dye to the BB-chromatids occurs to produce the B-dark SCD. It was revealed that not only the time but the temperature at which chromosome preparations are kept prior to use considerably affect the occurrence of SCD.